Aircraft-launched flares of various types have been used for many purposes. For example, it is often desirable to light a particular area at night. A flare may be used to produce light for search and rescue operations or for various military purposes. It is also well known to employ flares as a decoy tactic. That is, a flare may be used to cover the path of an aircraft through a particular area. One common situation is when the aircraft is encountering anti-aircraft fire. The use of a flare can distract the anti-aircraft fire sufficiently to allow the aircraft to proceed safely on its course.
Anti-aircraft missiles are commonly used in modern warfare. Such missiles may be launched from the ground or they may be launched from another aircraft. Many of this type of missile are designed to seek particular types of emissions characteristic of aircraft. Such emissions often take the form of heat and infrared light. Thus, "heat-seeking" missiles are often used against aircraft.
In this context, it is desirable to provide a flare that produces the type of emissions sought by the missile in order to distract the missile from the actual aircraft. Thus, flares that emit heat and infrared are well known and have been used for many years
Conventional decoy flare materials have been a combination of magnesium and polytetrafluoroethylene (PTFE or "Teflon.RTM."). These compositions are known widely as magnesium-Teflon.RTM. flare compositions. These formulations produce a black body emission spectrum which has been used as a decoy for jet engines.
Current methods of producing magnesium-PTFE flare compositions require the use of solvents that are ozone-depleting or flammable. In one currently used method, the composition is produced by depositing the binder on the pyrotechnic mixture through solvent loss using, for example, acetone or methyl-ethyl ketone. The mixture is dried, after which it is consolidated through pressing or extrusion operations. In a second method, a binder such as Viton A.RTM., which is a fluorinated ethylene propylene copolymer sold by DuPont, is deposited on the pyrotechnic mixture through polymer precipitation methods using hexane and acetone. The dried pyrotechnic powder is then consolidated through pressing or extrusion operations. This method requires large quantities of acetone and hexane, which are flammable, to carry the Viton A.RTM. binder. The solvents used in these methods have been the source of many fires during the processing of decoy mixes.
An additional problem with conventional magnesium-PTFE compositions is that they are very sensitive. Moreover, such compositions require extensive operator exposure during mixer dumping, oven loading, and material break-up operations. Traditional methods have proven disadvantageous, as the processing and handling of conventional flare compositions is dangerous and has resulted in many injuries and even deaths. An additional problem with conventional magnesium-PTFE compositions is that such compositions typically require expensive ingredients such as specialty binders and spherical magnesium.
Accordingly, it would be a significant advancement in the art to provide compositions and methods of producing decoy flares that overcame the identified problems of producing conventional flares. In particular, it would be an advancement to provide flare compositions that eliminate the safety risks associated with handling unconsolidated pyrotechnic powder. It would also be an advancement in the art to provide flare compositions and methods of production that eliminate ozone-depleting or flammable solvent emissions that accompany production. It would be a further advancement in the art to provide such flare compositions that could be manufactured using traditional press/extrusion techniques or using a twin screw extruder.
It would also be an advancement to provide such compositions that exceed the radiometric performance of conventional magnesium-PTFE infrared decoy flare compositions. It would be a further advancement in the art to provide such compositions that cost less than conventional flare compositions to produce.
Such compositions and methods for producing decoy flares are disclosed and claimed herein.